Translation and MicroRNA Synthesis

Question 1

Describe the processes in translation

Answer 1

1- Takes place on 80S ribosome in the rough ER. Ribosomes have two subunits (rRNA and protein complexes). 2- mRNA is moved through a groove at the junction of the two RNA molecules. 3- tRNAs with complementary codon sequences bring the relevant amino acids to the ribosome site. 4- Translation terminates at the stop codon (e.g. UAG).

Question 2

What are microRNAs?

Answer 2

They are small non-coding RNA sequences that are produced in the same way as proteins. Their role= post-transcriptional regulators- they regulate the translation of mRNA after its been generated.

Question 3

How are they produced?

Answer 3

They are produced in the nucleus as long hairpin structures and processed to produce short sections of RNA <30 bases in length.

Question 4

What do microRNA bind to?

Answer 4

RISC

Question 5

RISC?

Answer 5

RNA induced silencing complex

Question 6

What do microRNA do after they bind to RISC?

Answer 6

microRNA is complimentary to the target mRNA sequence so it will bind to the mRNA, leading to cleavage of the target mRNA.

Question 7

What does cleaving target mRNA lead to?

Answer 7

down-regulation of protein expression.